reset my OC help!

[Darkhorse!]

when I was playing Guild wars for a couple hours in this so cal heat, then the game lagged so i minimize the screen to see whats up then it say on that nvidia screen "not giving enough power to the video card so in order not experince lockups or crash ur oc has gone back to stock" so i shutdown my comp and cool it down and i fire her up again some time i would get the same error please help



bfg 6800gt oc pci-e
psu antec tu blue 480

 

[Ether]

All options, not necessarily a list of must do's:
Make sure the 6 pin connector is all the way in.
Reseat the card.
Reinstall drivers.